1. Field of the Invention
The present invention relates to a pad clip for use in a disc brake which is used to brake a vehicle and, in particular, to an improved pad clip which holds a friction pad movable in the axial direction of a rotor in such a manner that the sliding resistance of the friction pad with respect to a support member can be reduced.
2. Related Art
Conventionally, in a disc brake, there are mounted on a support member a pair of friction pads which are to be disposed in such a manner that they can hold a rotor between them, the rotor is held by and between a caliper reaction portion and a hydraulic cylinder device, and, when the friction pads are to be rotated together with the rotor, the side edge portions of the friction pads are anchored by a support member, thereby being able to exert a brake force. Since the friction pads are moved in such a manner that they are in contact with the rotor surface while they are being held by the support member, in the anchor portions of the disc brake between the friction pads and the support member, there are mounted a pair of pad clips which are used to reduce the sliding friction of the friction pads. These pad clips are mounted on the anchor surfaces of the support member facing the side edges of the friction pads, and are respectively so formed after the anchor shapes of the support member as disclosed, for example, in Japanese Utility Model Publication No. Hei. 2-18353.
Here, FIG. 4 is an enlarged section view of the main portions of a conventional pad clip. As shown in FIG. 4, a friction pad 1 includes a projecting portion 1A, while a support member 2 includes a recessed groove portion 2A which corresponds to and can be fitted with the projecting portion 1A. And, the projecting portion 1A and recessed groove portion 2A cooperate together in forming a recess and projection fitting portion, so that a brake torque generated by the friction pad 1 can be received by the support member 2. Here, between the friction pad 1 and the support member 2, there is interposed a pad clip 3 which is used to reduce the sliding friction produced between them. This pad clip 3 includes a U-shaped portion 3A, which is so formed as to have a shape after the shape of a support projecting portion 2B formed in the support member 2 and is used to hold the present support projecting portion 2B between the two sides thereof, and, due to the holding action of the present U-shaped portion 3A, the pad clip 3 can be retained by the support member 2. And, downwardly of the U-shaped portion 3A, through a side end face 3B which provides the inmost portion of the recess and projection fitting portion and is to be closely contacted with the recessed groove portion 2A, there is formed a rotor diameter direction pressing portion 3C which is used to press against the friction pad 1 outwardly in the rotor diameter direction; and, the friction pad 1 can be retained due to such pressing or energizing action of the rotor diameter direction pressing portion 3C.
In the conventional pad clip having the above-mentioned structure, there is provided a clearance (in FIG. 4, shown by a dimension a and a dimension b) in the recess and projection fitting portion, for the purpose of reducing the sliding friction between the friction pad and the support member. However, in the above-mentioned condition, if a brake operation is executed, then there is produced a moment of rotation in the friction pad due to its frictional contact with the rotor and there are thereby produced a couple of forces around the holding portion thereof. And, due to the production of the couple of forces, the friction pad is rotated by an amount corresponding to the clearances, thereby allowing the friction pad to tap the pad clip (the support member). This tapping operation is generated continuously by the vibration of the caliper caused by the braking operation and thus, due to the tapping operation of the friction pad on the pad clip (the support member), between the friction pad and an anti-rattle spring (the support member), there is generated a rattling noise which provides the cause of noise in the braking operation.